Most crash-repair, insurance-grade auto body work is done with a MIG.
All high-end restoration shop auto body work is done with a TIG.
To the OP: how much do you plan to use this machine, and how good are your skills? I've got gas, MIG, and TIG, and I'm REALLY liking the TIG. If you can gas weld, you'll pick up TIG pretty quickly, but it really does take a lot of practice. Once you get it, you won't look back. I got one of the AlphaTIG units a couple of years ago, primarily for patch panels, but I'm now getting into building aluminum items as well. It's a really nice, cost-effective unit for home shop use. No, it's not a Miller or Lincoln, but it's half the price. The new 201 model even comes with a real foot pedal (I had to buy an aftermarket upgrade for my older unit). There are now several imported inverter TIGs that are comparable in that price range, so you have a choice.